In known-type processes the light beam colour percentages reaching the paper are greatly influenced by the type of negative support used and the exposure quality of the image contained on it: the light beam is in fact strongly chromatically and densitometrically affected by the type of support, so that results can vary greatly.
This problem is at present resolved by providing a considerable number of colour filters to filter the light coming from the source before it reaches the negative support. The drawback with this process is that for each type of negative support suitable filters are required and have to be painstakingly selected.
In modern enlargers the selection of the correct filters from the set mounted on the enlargers is made by analyzing the beam after said filters have been selected, which is usually done automatically, and making a final choice after some test runs of this nature. Amateur photographers, however, usually possess non-automatic devices and thus have to try out several different filter combinations before obtaining a satisfactory result.
A principal aim of the present invention is to obviate the above drawbacks by providing a device which permits of obtaining a light beam having a chromatic composition that is not influenced by the quality and type of negative support bearing the image to be developed.
An advantage of the device is that it obtains the desired result while remaining very simple and economical.